1. Field of the Invention
This specification relates to a compressor and a method for controlling the same, and more particularly, a compressor which controls a motor thereof by generating a control signal related to a driving thereof by the compressor itself, and a method for controlling the same.
2. Background of the Invention
In general, a compressor is an apparatus for converting mechanical energy into compression energy in a compressible fluid, and constitutes a part of a refrigerating device, for example, a refrigerator, an air conditioner and the like.
Compressors are roughly classified into a reciprocating compressor, a rotary compressor, and a scroll compressor. The reciprocating compressor is configured such that a compression space for sucking and discharging operating gas is formed between a piston and a cylinder and a refrigerant is compressed as the piston linearly reciprocates in the cylinder. The rotary compressor is configured such that a compression space for sucking and discharging operating gas is formed between an eccentrically-rotatable roller and a cylinder and a refrigerant is compressed as the roller eccentrically rotates along an inner wall of the cylinder. The scroll compressor is configured such that a compression space for sucking and discharging operating gas is formed between an orbiting scroll and a fixed scroll and a refrigerant is compressed as the orbiting scroll rotates along the fixed scroll.
The reciprocating compressor sucks, compresses and discharges a refrigerant by linearly reciprocating the piston within the cylinder. The reciprocating compressor is classified into a recipro type and a linear type according to a method of driving the piston.
The recipro type refers to a type of reciprocating compressor of converting a rotary motion of a motor into a linear reciprocating motion by coupling the motor to a crankshaft and coupling a piston to the crankshaft. On the other hand, the linear type refers to a type of reciprocating compressor of reciprocating a piston using a linear motion of a linearly-moving motor by connecting the piston to a mover of the motor.
The reciprocating compressor includes a motor unit generating a driving force, and a compression unit compressing fluid by receiving the driving force from the motor unit. A motor is generally used as the motor unit, and specifically the linear type reciprocating compressor uses a linear motor.
The linear motor directly generates a linear driving force, and thus does not require a mechanical conversion device and a complicated structure. Also, the linear motor can reduce a loss due to an energy conversion, and remarkably reduce noise by virtue of the non-existence of a connection portion from which friction and abrasion are caused. Also, when the linear type reciprocating compressor (hereinafter, referred to as a linear compressor) is applied to a refrigerator or air conditioner, a compression ratio can vary by changing a stroke voltage applied to the linear compressor. Accordingly, the compressor can also be used for a control of varying a freezing capacity.
A compressor installed at a refrigerator may receive a control signal from a controller (or a refrigerator controller) installed at a refrigerator body, and may be driven according to the received control signal. That is, the refrigerator controller may control a driving cycle of a linear motor by applying a control signal to a driving unit or an inverter connected to the linear motor, in order to control a cooling capacity of the compressor.
Accordingly, in case of an inexpensive refrigerator not having such a controller (or a refrigerator controller) or an inexpensive refrigerator which cannot match a driving cycle of a linear motor, it is difficult to apply such a general compressor thereto.
In order to solve such a problem, required are a compressor capable of receiving only a control signal related to on/off thereof from the outside, and capable of generating a control signal related to a driving thereof, and a method for controlling the same. Further, required are a compressor which can be applied to a refrigerator not having a cycle matching function, and a method for controlling the same.